Choosing Materials for Outdoor Signs

For any interpretive project, good planning makes design decisions easy. Planning is especially important in choosing materials for outdoor signs, since they will be subjected to a variety of site-specific environmental factors including weather, rigorous maintenance routines and equipment, graffiti, pollution, wild animals and even target practice.

One client we worked with had installed a porcelain enamel map at their site in a remote area of the Southern California desert. After only one year, their beautiful (and expensive) map was riddled with bullet holes! We were able to replace it with a more reasonably priced, high-pressure laminate (HPL) map, which isn’t so easily damaged by bullets.

In the following article, I’ll introduce you to the materials I most commonly recommend for use in outdoor interpretative exhibits — both for exhibit panels and the supporting structures. I also provide a list of questions you and your team can ask in order to determine what qualities to look for in materials. I’m also providing matrices I’ve developed (and which I use myself) for weighing project needs against the pros and cons of different materials. Lastly, I’ve listed questions you should ask your fabricator when considering any new material.

In the future, I’ll be regularly posting tips on Spark about planning for interpretive panels. If there is something in particular you’d like me to address, please mention it in a comment at the end of this article.

Some common panel materials

One of the materials clients most often select is high-pressure laminate (HPL). It stands up well to many outdoor settings, has very good image quality, and is reasonably priced. Another popular material is fiberglass embedded digital graphics.  These products can last up to ten years in protected areas, have decent image quality, and cost a little less than HPL. There are also a variety of vinyl graphic options and combinations available. These can be good, quick, low-cost solutions for temporary signs that will last up to three years in protected areas. Porcelain enamel, etched metal, and etched stone are all extremely durable and the most environmentally friendly because of their production process and ability to be recycled. On the other hand, these products vary in image quality and have the highest up-front costs.

Some common support materials

Since supports don’t have to carry content, your primary considerations are strength and durability. Aesthetically, you may want the support material to work  thematically with the content. There is a huge variety of materials on the market for panel supports. I’m listing just a few of the materials I most often use.

Metal is the sturdiest support material. Weathering steel, best known as “COR-TEN steel,” forms a stable rust-like finish, eliminating the need for paint. It is virtually maintenance free, but can be hard to obtain, and the price varies with market availability. Galvanized steel also requires little or no maintenance, and it is both readily available and relatively inexpensive. Most other metals will require some kind of finish treatment (clear coat, paint, sandblast, etc.) for outdoor life.

Wood may or may not require a finish treatment, but should be combined with a metal or concrete foundation to avoid rot and termites. Pressure-treated wood can go straight into the ground, but releases harmful chemicals into the soil. Composite wood (Trex®) products can also go straight into the ground and are made from recycled materials. Currently, none of the composite wood products are recyclable.

Fiberglass is fun to work with because it can be formed into almost any shape, and can achieve a high aesthetic. Color can be either embedded in the resins or surface applied using appropriate paints. However, it is usually expensive due to labor and material costs, and since it isn’t recyclable, it’s less environmentally-friendly than the other options.

What to know before choosing materials

As you can see, choosing materials for both panels and supports is a question of weighing pros and cons to find the best solution, or combination of solutions, for your particular project. There is no such thing as the “ideal” material for outdoor panels. For any given project, I ask my clients a series of questions to help them determine the project’s requirements:

1. What’s the budget?
2. What’s the schedule?
3. What’s the life expectancy of the sign program?
4. What’s the content? All text? Photos, maps, illustrations?
5. What image quality, and level of detail does the project’s content require? How many colors will it require?
6. What’s the physical location and environment? Urban or remote? What is the terrain like? Weather exposure? How likely is vandalism? Are there various mounting options?

Using matrices to weigh your options

After content for an outdoor panel has been determined, and we know the answers to the above questions, I sit down with my clients to choose materials. We use these matrices to make sure we’re clear about the best choices, and that we’re making decisions based on the extent to which the materials meet the project’s needs.

Panel Material Matrix (PDF, 460KB)

Support Material Matrix (PDF, 444KB)

What to ask when you’re considering a particular material

I haven’t included every single available material in the matrices above. Still, any time you’re considering a material to display your carefully crafted content, you need to know just what that material is going to deliver. You can use this list of questions as a reference to make sure you have all the answers you need.

1. What is the availability and lead time of the product?
2. Is the image quality of the material appropriate for your content?
3. What is the lifetime of the product? And specifically, what is the life expectancy of the product in the environment of the desired location?
4. What is involved in the installation of the product?
5. How is the product maintained? Are there recommended maintenance schedules or care products and procedures?
6. What are the initial costs?
7. What are the environmental considerations, i.e., recycled content, FSC-certifications, recyclability?
8. What is the material’s lifetime aesthetic in context of the sign program’s life span? In other words, will the panel and support materials look good as long as the you want the sign program to last?
9. What is the lifetime value? Is it a good value for the length of time it will be in service?

Again, when we know the answers to the above questions, we can determine our best choices and make decisions based on the extent to which the materials meet the project’s needs.

Well developed content is fundamental. Keeping abreast of the advances in sign technology is important. But good planning is essential in effectively and aesthetically communicating your message to the visitor. Happy planning!